An **air conditioner** is a system designed to stabilize the air temperature and humidity within a confined space, typically for cooling purposes. It operates by drawing warm indoor air into the unit, passing it over evaporator coils filled with refrigerant to absorb heat, and then exhausting that heat outdoors while recirculating the cooled air. Beyond mere temperature control, modern units often improve **indoor air quality** by filtering out dust, pollen, and other airborne particles, creating a more comfortable and healthy environment during periods of high heat or humidity.